US8571094B2 - Noise measurement method and a related receiving digital subscriber line modem - Google Patents

Noise measurement method and a related receiving digital subscriber line modem Download PDF

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US8571094B2
US8571094B2 US11/302,267 US30226705A US8571094B2 US 8571094 B2 US8571094 B2 US 8571094B2 US 30226705 A US30226705 A US 30226705A US 8571094 B2 US8571094 B2 US 8571094B2
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digital subscriber
subscriber line
noise
line modem
frequency
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US20060126708A1 (en
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Etienne André Hubert Van Den Bogaert
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RPX Corp
Nokia USA Inc
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Alcatel Lucent SAS
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L1/00—Arrangements for detecting or preventing errors in the information received
    • H04L1/20—Arrangements for detecting or preventing errors in the information received using signal quality detector

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  • the present invention relates to a method for Noise measurement as described in the preamble of claim 1 and the related Receiving Digital Subscriber Line modem as described in the preamble of claim 6 .
  • the transmission of data of a dataflow is done using Discrete Multi Tone and is based on quadrature amplitude modulation (QAM) wherein bits of the data flow are modulated on a carrier-signal comprising many tones.
  • QAM quadrature amplitude modulation
  • This modulation is done by mapping a number of bits of the dataflow as a single symbol on each tone of a plurality of tones of the carrier-signal.
  • This number of bits at first is at transmission mapped as a symbol on a predetermined constellation point of a plurality of constellation points where each of the constellation points in FIG. 1 is presented as a dot. Subsequently, the constellation point whereon a symbol is mapped is used for modulating the symbol onto the carrier signal.
  • the number of bits that can be modulated as a single symbol on a single tone of the carrier-signal depends amongst others on the signal-to-noise ratio of the modulated signal.
  • This modulated data-signal comprising a plurality of tones carriers each tone carrying a symbol towards the receiver.
  • the receiving modem at reception of the symbols modulated on the tones of the carrier-signal and transmitted by the transmitting modem, starts demodulating the received data-signal and subsequently performs the demapping, called mapping in the opposite direction, of such a received symbol onto a constellation point.
  • the received symbol is demapped on the constellation point closest to the received symbol. Due to noise on the communication line the received symbol which is transmitted on a certain constellation point S 1 is received within the decision area of an adjacent or possibly another constellation point S 2 as presented in FIG. 1 .
  • the QAM demodulation and demapping at the receiver is based on hard decisions and the process of corrupt symbol detection as shown in FIG. 1 .
  • the distance between the received symbol and the constellation point whereon the received symbol is remapped is measured as noise. This means that the measured noise will never exceed the maximum noise distance within one decision region, which is
  • the receiving modem will sense a smaller noise increase than the real noise increase.
  • An object of the present invention is to provide a noise measurement method of the above known type and a related system but wherein the noise measurement is improved.
  • this object is achieved by the Noise measurement method as described in claim 1 , the Receiving Digital Subscriber Line modem as described in claim 6 .
  • this object is achieved due to the fact that the receiving modem determines a frequency of the symbols incorrectly demapped, where this frequency of incorrect demapped symbols is proportional to the level of the noise and consequently the noise margin, and subsequently corrects the noise measurement using this frequency of the symbols incorrectly demapped.
  • the determination of the increased frequency is based on the determination of symbols received in an erasure zone.
  • a symbol received in the erasure zone is a symbol received outside the area for demapping received symbols and hence indicating an error situation.
  • the number of symbols received in the erasure zone i.e. the number of incorrect demapped symbols, is used for correcting the noise
  • the determination of the increased frequency of symbols incorrectly demapped is based on the receiving modem determining a deviation from a normal distribution of the measured noise on the received symbols. Where the deviation of the normal distribution increases, the noise level increases and consequently the noise margin decreases. In other words the deviation from the normal distribution is proportional to the noise level increase.
  • the correction of the noise measurement then can be made based on this frequency of measured incorrectly received symbols.
  • a device A coupled to a device B should not be limited to devices or systems wherein an output of device A is directly connected to an input of device B. It means that there exists a path between an output of A and an input of B which may be a path including other devices or means.
  • FIG. 1 represents the QAM hard-decision symbol detection
  • FIG. 2 represents a Digital Subscriber Line communications system
  • FIG. 3 represents the functional representation of the transmitter DTE and the receiver DRE as presented in FIG. 2 ;
  • the essential elements of the Digital Subscriber Line communications system network of the embodiment according to the present invention are a transmitter DTE, in this embodiment chosen to be a central office and a receiver here chosen to be a user terminal.
  • the transmitter DTE is coupled to a communications network CNW which here is chosen to be the Internet and is coupled to the receiver DRE over a Digital Subscriber Line DSL.
  • the Digital Subscriber line communications system of the present invention comprises a transmitting Digital Subscriber Line modem DTE for transmitting symbols of a data-signal by modulating each of these symbols on a tone of a plurality of tones of a carrier signal, towards the Receiving Digital Subscriber Line modem DRE and a Receiving Digital Subscriber Line modem DRE for demodulating the transmitted data-signal and retrieving the modulated symbols from the received signal.
  • a transmitting Digital Subscriber Line modem DTE for transmitting symbols of a data-signal by modulating each of these symbols on a tone of a plurality of tones of a carrier signal, towards the Receiving Digital Subscriber Line modem DRE and a Receiving Digital Subscriber Line modem DRE for demodulating the transmitted data-signal and retrieving the modulated symbols from the received signal.
  • Digital Subscriber Line communications network usually comprises a plurality of transmitters and receivers.
  • the receiver DRE first comprises a signal receiving part SRP that is adapted to receive the symbols of a data-flow transmitted by a DSL transmitter DTE where these symbols of the data-flow are modulated on tones of a carrier according to an XDSL standard.
  • the Receiving Digital Subscriber Line modem further comprises the following relevant parts: a signal demodulation part SDP that is able to demodulate the received signal and determine the transmitted symbols from the received signal, a symbol demapping part SMDP that is adapted to perform the demapping of said symbol received onto a constellation point S 2 , a noise measuring part NMP that is adapted to determine the noise on the digital Subscriber line DSL based on the distance between the received symbol R and the determined constellation point S 2 .
  • the Receiving Digital Subscriber Line modem DRE comprises a Deviation frequency determination part DFDP, that is able to determine a frequency of the incorrectly demapped symbols and a Noise measurement correction part NMCP that is adapted to correct the noise determined, using the frequency of the symbols incorrectly demapped.
  • DFDP Deviation frequency determination part
  • NMCP Noise measurement correction part
  • the Signal reception Part SRP has an input that is at the same time an input-terminal I 1 of the receiver DRE. Further, the signal demodulating part SDP is coupled with an input to an output of the signal reception part SRP and the symbol demapping part SMDP is coupled with an input to an output of said signal demodulating part SDP.
  • the noise measuring part NMP is coupled with a first input to an output of the symbol demapping part SMDP and coupled with a second input to an input of the symbol demapping part SMDP.
  • the frequency determination part DFDP is coupled with a first input to an output of the noise measuring part NMP and further coupled with a second input to an input of the noise measuring part NMP.
  • the noise measurement correction part NMCP is coupled with an input to an output of said deviation Frequency determination part DFDP. Furthermore the deviation Frequency determination part DFDP has an output that is at the same time an output-terminal O 1 of the receiver DRE.
  • a data signal is forwarded from a Digital Subscriber Line transmitting modem DTE towards the Digital Subscriber Line receiving modem DRE.
  • This transmitted signal comprises a series of modulated Quadrature amplitude modulated symbols, which are modulated according to a 4 bits QAM modulation scheme as presented in FIG. 1 .
  • the signal reception part SRP of the Receiving Digital Subscriber Line modem DRE receives this analogue data signal carrying the modulated symbols transmitted by the transmitting Digital Subscriber Line modem.
  • the signal reception part SRP converts the received data-signal into a digital output data signal.
  • An analogue part of the signal reception part SRP optionally takes care of filtering, amplification, echo cancellation, etc.
  • the resulting signal is digitised before being optionally filtered, equalised, windowed etc. All of these operations are performed in the time domain.
  • the signal then is passed to the signal demodulating part SDP which will transform the time domain signal into a frequency domain signal (or a coded domain signal in case code division multiple access CDMA is applied).
  • the signal demodulation part SDP demodulates the received data signal and retrieves the transmitted symbols, each representing 4 data-bits, from the demodulated data signal. Then the symbol demapping part SMDP performs the demapping of the received symbols on a constellation point. For instance the transmitted symbol is symbol S 1 ( FIG. 1 ) the received symbol R 1 is equal to the transmitted symbol plus noise, in this case it is received within the decision area of symbol S 2 (see FIG. 1 ). Next, the symbol demapping part SMDP will apply decision rules (hard-decision rules) to relate the received symbol to the expected sent constellation point. This constellation point corresponds to a series of bit values, hence it is carrying information.
  • decision rules hard-decision rules
  • the symbol demapping part SMDP then demaps the received symbol R 1 onto the calculated constellation point, which here actually is constellation point S 2 (the here described example is valid for hard-decision based rules). Hence, after the demapping process the symbol is received at constellation point S 2 .
  • the symbol demapping part SMDP provides the noise measuring part NMP with the information about the received symbol and the demapped constellation point.
  • the noise measuring part NMP measures the noise based on the difference between the received symbol R 1 and the determined constellation point S 2 by applying a metric adapted to compute the difference between the received symbol and the demapped constellation point. This metric gives the measured noise
  • the by the receiving modem DRE measured and perceived noise is only the distance between R 1 and S 2 .
  • the transmitted symbol S 1 in case of no noise and errors should have been received at constellation point S 1 .
  • the real actual noise is represented by the distance between the transmitted symbol S 1 and the received symbol R 1 as presented in FIG. 1 is substantially larger.
  • the Receiving Digital Subscriber Line modem DRE further comprises a deviation frequency determination part DFDP, which determines a frequency of incorrectly demapped symbols.
  • This deviation frequency determination part DFDP may use a deviation from a normal distribution of the received symbols for determining the frequency of incorrectly demapped symbols, or may use the frequency of using a number of symbols received in the erasure zone. Even a combination of both the deviation of the normal distribution together with the number of symbols received in the erasure zone can be used.
  • the deviation frequency determining part DFDP computes, based on the data coming from the noise measuring part NMP, the deviation of the measured noise from a normally (gaussian) distributed noise.
  • the noise measurement error is small such that the measured noise has the characteristics of a gaussian distributed noise.
  • the noise measurement error becomes important and distorts the noise probability distribution function. Therefore, a deviation from the properties of the gaussian distribution can be detected and used to identify a higher noise.
  • the ratio between the second order moment squared (also known as variance squared) and the fourth order moment is fixed and known.
  • the probability density function is not gaussian any more and the above said ratio is not any more equal to the ratio for gaussian distributions and hence indicating noise measurement errors.
  • variable N denotes the sequence of symbols for which the second order moment and the fourth order moment are computed.
  • Another possibility is to detect a deviation from the gaussian distribution at the edges of the decision regions. Indeed, for a gaussian distribution, the probability density function (pdf) decreases closer to the edges. When introducing noise measurement errors due to hard-decision demapping, the measured noise pdf will increase closer to the edges, indicates that noise measurement errors are introduced. It is further to be noted that this example is in fact the same as computing the ratio between the second order moment and the fourth order moment.
  • a QAM symbol consists of decision regions and one big region outside the decision regions called the erasure zone.
  • the received symbol R 2 potentially moves outside the decision region, i.e. into the erasure zone EZ.
  • Using the distance between the received point R 2 within the erasure zone EZ and the nearest decision point also introduces a noise measurement error. Therefore, this distance has to be multiplied by a weight factor to take into account the probability that the transmitted point was not the nearest point to the received point.
  • noise measurement correcting part NMCP takes the output of the deviation frequency determining part DFDP to take actions to correct the noise measurement data to provide more accurate noise measurement data.
  • the noise measurement correcting part NMCP uses as an input the deviation of the noise from the normal distribution, the measured noise and/or the erasure data.
  • the noise measurement correcting part NMCP takes these inputs to decide whether the measured noise is correct or not. If the measured noise is not correct, the noise measurement correcting part NMCP applies a correction based on the deviation of the normally distributed noise and the data related to erasures.
  • the correction based on the deviation of the normally distributed noise can be stored beforehand in a look-up table, where the measured noise has to be multiplied by a correction-factor determined by the deviation of the normal distribution. Such a look-up table is presented in Table 1,
  • the noise distribution is Gaussian.
  • alpha deviates from the aforementioned value, it indicates a deviation from the Gaussian distribution.
  • Table 1 shows the values of several parameters for a decision region with width equal to 100.
  • Sigma is the theoretical value of the standard deviation of the noise, and as can be seen from the table, the measured standard deviation is very close to the theoretical value. This has been simulated for 100000 symbols. If the theoretical value for the noise standard deviation increases, the measured value deviates more and more from the theoretical value. This is due to demapping errors. Looking at the value of alpha, it shows alpha also deviates from the first entry in the table. Hence, measuring a deviation of alpha, shows a deviation from the Gaussian noise distribution. This deviation can then be corrected.
  • the noise correction based on erasure data can be done by multiplying the noise distance of the erasure with a weight that is a function of the constellation. Every constellation has a different probability of having received points within the erasure zone in function of the noise. For example, for a 4-QAM as presented in FIG. 1 , the probability of receiving a symbol in the exposure zone when the noise increases with 6 dB (this corresponds to a certain alpha), is much higher than the probability of receiving a symbol within the erasure zone with a 12-bit-QAM constellation when the noise increases with 6 dB.
  • the weights increase with increasing bitloading.
  • the weight for a 4-QAM i.e. a 2-bit-QAM
  • the weight for a 14-bit-QAM is equal to 2.5. If an erasure is encountered for a 4-QAM symbol, the measured noise has to be multiplied with 1.001 (the weight given in table 2), whereas, if an erasure is encountered in a 14-bit-QAM constellation, the measured noise has to be multiplied with the corresponding weight equal to 2.5.
  • This n corrected is then used to update the noise measurement with the latest measured sample.
  • the noise measurement correction part NMCP corrects the noise measured by the noise measurement part NMP, using the frequency of the symbols incorrectly demapped.
  • a look-up table can be implemented to provide the real noise as output for some given demapping error frequency.
  • the noise measurement correction part NMCP may forward the corrected noise level towards the transmitting Digital Subscriber Line modem TMM that may use this corrected noise level for adapting the transmit power.
  • the present invention may additionally be applied in a Pulse Amplitude Modulation scheme as used in Symmetric High-bitrate Digital Subscriber Line or in any mobile analogous modulation.

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  • Engineering & Computer Science (AREA)
  • Quality & Reliability (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Digital Transmission Methods That Use Modulated Carrier Waves (AREA)
  • Monitoring And Testing Of Transmission In General (AREA)
  • Arrangements For Transmission Of Measured Signals (AREA)
  • Communication Control (AREA)
  • Telephonic Communication Services (AREA)
US11/302,267 2004-12-15 2005-12-14 Noise measurement method and a related receiving digital subscriber line modem Active 2032-06-28 US8571094B2 (en)

Applications Claiming Priority (3)

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EP04292999.2 2004-12-15
EP04292999A EP1672827B1 (de) 2004-12-15 2004-12-15 Verfahren zur Rauschmessung und entsprechendes empfangendes DSL-Modem.
EP04292999 2004-12-15

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CN (1) CN100534080C (de)
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Publication number Priority date Publication date Assignee Title
US20070206700A1 (en) * 2006-03-06 2007-09-06 Mediatek Inc. Quadrature Amplitude Modulation receiver and diagnostic method thereof
US7720633B2 (en) * 2007-01-10 2010-05-18 Futurewei Technologies, Inc. Bivariate histogram for impulse noise monitor
CN103532905B (zh) * 2012-07-05 2017-09-19 北京新岸线移动通信技术有限公司 基于硬判决的信噪比估计方法和装置
US9420511B2 (en) 2012-11-01 2016-08-16 Intel Corporation Signaling QoS requirements and UE power preference in LTE-A networks
US9106470B2 (en) * 2012-12-03 2015-08-11 Qualcomm Incorporated Enhanced decoding and demapping method and apparatus for QAM data signals

Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3845466A (en) * 1970-11-18 1974-10-29 California Inst Of Techn System and method for character recognition
US5689444A (en) * 1995-06-07 1997-11-18 The United States Of America, As Represented By The Secretary Of Commerce Statistical quality control of wind profiler data
GB2319148A (en) 1996-09-27 1998-05-13 Plessey Telecomm Noise level determination in a quadrature amplitude modulated signal
US6108373A (en) 1993-12-15 2000-08-22 Alcatel Telspace Process and device for detecting loss of carrier recovery and of determining the Eb/No ratio of a digital transmission link
US20030152157A1 (en) * 2002-02-12 2003-08-14 Alcatel Method and arrangement to synchronize a multi-carrier transmission system
US20030188254A1 (en) * 2002-02-28 2003-10-02 Itay Lusky Error correction code parameter selection in a communication system
US20030210749A1 (en) * 2002-05-09 2003-11-13 Hosein Asjadi Receiver
US20040078168A1 (en) * 2000-11-13 2004-04-22 Alexander Horch Method and a system for evaluation of static friction
US20050190800A1 (en) * 2003-12-17 2005-09-01 Intel Corporation Method and apparatus for estimating noise power per subcarrier in a multicarrier system
US20060083324A1 (en) * 2004-10-15 2006-04-20 Desjardins Philip Method and apparatus for detecting transmission errors for digital subscriber lines

Patent Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3845466A (en) * 1970-11-18 1974-10-29 California Inst Of Techn System and method for character recognition
US6108373A (en) 1993-12-15 2000-08-22 Alcatel Telspace Process and device for detecting loss of carrier recovery and of determining the Eb/No ratio of a digital transmission link
US5689444A (en) * 1995-06-07 1997-11-18 The United States Of America, As Represented By The Secretary Of Commerce Statistical quality control of wind profiler data
GB2319148A (en) 1996-09-27 1998-05-13 Plessey Telecomm Noise level determination in a quadrature amplitude modulated signal
US20040078168A1 (en) * 2000-11-13 2004-04-22 Alexander Horch Method and a system for evaluation of static friction
US20030152157A1 (en) * 2002-02-12 2003-08-14 Alcatel Method and arrangement to synchronize a multi-carrier transmission system
US20030188254A1 (en) * 2002-02-28 2003-10-02 Itay Lusky Error correction code parameter selection in a communication system
US20030210749A1 (en) * 2002-05-09 2003-11-13 Hosein Asjadi Receiver
US20050190800A1 (en) * 2003-12-17 2005-09-01 Intel Corporation Method and apparatus for estimating noise power per subcarrier in a multicarrier system
US20060083324A1 (en) * 2004-10-15 2006-04-20 Desjardins Philip Method and apparatus for detecting transmission errors for digital subscriber lines

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
Dr. Dennis J. Rauschmayer, "ADSL/VDSL Principles, A Practical and Precise Study of Asymmetric Digital Subscriber Lines and Very High Speed Digital Subscriber Lines", Chapter 6, p. 159.

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EP1672827A1 (de) 2006-06-21
CN100534080C (zh) 2009-08-26
EP1672827B1 (de) 2009-02-11
ATE422749T1 (de) 2009-02-15
CN1791083A (zh) 2006-06-21
DE602004019438D1 (de) 2009-03-26
US20060126708A1 (en) 2006-06-15

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